Neo4jConfiguration有循環引用

Question

我在spring-boot應用程序中使用spring-data-neo4j。通過繼承Neo4jConfiguration類，我按照spring.io guides和許多其他地方的建議進行了配置。這在數據庫位置在所提供的示例中被硬編碼時起作用。但是，當我想使用佔位符從屬性文件中檢索數據庫位置時，它不會被檢索到，並且我會得到空值。下面的代碼

@Configuration 
@EnableNeo4jRepositories(basePackageClasses = {MyRepository.class}) 
public class Neo4jConfig extends Neo4jConfiguration { 

    @Value("${neo4j.location}") 
    private String neo4jDatabaseLocation; 

    @Bean 
    public GraphDatabaseService graphDatabaseService() { 
     return new GraphDatabaseFactory() 
       .newEmbeddedDatabase(neo4jDatabaseLocation); 
    } 
    ... 

這通常可以在任何其他配置類，但不是在這一個，因爲Neo4jConfiguration class有標有@Autowired一些幾種方法。這會導致循環引用，並且未正確初始化。這可以在日誌中看到：

2014-09-06 20:59:45.168 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Registered injected element on class [c.m.f.Neo4jConfig$$EnhancerBySpringCGLIB$$7165d752]: AutowiredFieldElement for private javax.validation.Validator org.springframework.data.neo4j.config.Neo4jConfiguration.validator 
2014-09-06 20:59:45.169 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Registered injected element on class [c.m.f.Neo4jConfig$$EnhancerBySpringCGLIB$$7165d752]: AutowiredMethodElement for public void org.springframework.data.neo4j.config.Neo4jConfiguration.setConversionService(org.springframework.core.convert.ConversionService) 
2014-09-06 20:59:45.169 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Registered injected element on class [c.m.f.Neo4jConfig$$EnhancerBySpringCGLIB$$7165d752]: AutowiredMethodElement for public void org.springframework.data.neo4j.config.Neo4jConfiguration.setGraphDatabaseService(org.neo4j.graphdb.GraphDatabaseService) 
2014-09-06 20:59:45.169 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Registered injected element on class [c.m.f.Neo4jConfig$$EnhancerBySpringCGLIB$$7165d752]: AutowiredFieldElement for private java.lang.String c.m.f.Neo4jConfig.neo4jDatabaseLocation 
2014-09-06 20:59:45.169 DEBUG 4665 --- [   main] o.s.b.f.s.DefaultListableBeanFactory  : Eagerly caching bean 'c.m.f.Neo4jConfig' to allow for resolving potential circular references 
2014-09-06 20:59:45.171 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Processing injected method of bean 'c.m.f.Neo4jConfig': AutowiredFieldElement for private javax.validation.Validator org.springframework.data.neo4j.config.Neo4jConfiguration.validator 
2014-09-06 20:59:45.182 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Processing injected method of bean 'c.m.f.Neo4jConfig': AutowiredMethodElement for public void org.springframework.data.neo4j.config.Neo4jConfiguration.setConversionService(org.springframework.core.convert.ConversionService) 
2014-09-06 20:59:45.183 DEBUG 4665 --- [   main] o.s.b.f.annotation.InjectionMetadata  : Processing injected method of bean 'c.m.f.Neo4jConfig': AutowiredMethodElement for public void org.springframework.data.neo4j.config.Neo4jConfiguration.setGraphDatabaseService(org.neo4j.graphdb.GraphDatabaseService) 
2014-09-06 20:59:45.184 DEBUG 4665 --- [   main] o.s.b.f.s.DefaultListableBeanFactory  : Creating shared instance of singleton bean 'graphDatabaseService' 
2014-09-06 20:59:45.184 DEBUG 4665 --- [   main] o.s.b.f.s.DefaultListableBeanFactory  : Creating instance of bean 'graphDatabaseService' 
2014-09-06 20:59:45.185 DEBUG 4665 --- [   main] o.s.b.f.s.DefaultListableBeanFactory  : Returning cached instance of singleton bean 'org.springframework.transaction.config.internalTransactionAdvisor' 
2014-09-06 20:59:45.185 DEBUG 4665 --- [   main] o.s.b.f.s.DefaultListableBeanFactory  : Returning cached instance of singleton bean 'org.springframework.transaction.config.internalTransactionAdvisor' 
2014-09-06 20:59:45.188 DEBUG 4665 --- [   main] o.s.b.f.s.DefaultListableBeanFactory  : Returning eagerly cached instance of singleton bean 'c.m.f.Neo4jConfig' that is not fully initialized yet - a consequence of a circular reference 

正如你可以看到我在這裏試圖實現的不是硬編碼數據庫位置。有沒有解決這個循環引用問題的方法？或者也許還有其他配置方式？由於這是一個spring-boot應用程序，我沒有任何Xml配置，如果可能的話我想保留它。

Answer 1

擬議的建議並沒有爲我使用Spring Framework版本。作爲一種解決方法，我在另一個不擴展Neo4jConfiguration的配置文件中定義了GraphDatabaseService bean。請注意，無論如何，這個Neo4jConfig類都是需要的。

Answer 2

您是否嘗試過在neo4jDatabaseLocation作爲參數傳遞：

@Configuration 
@EnableNeo4jRepositories(basePackageClasses = {MyRepository.class}) 
public class Neo4jConfig extends Neo4jConfiguration { 

    @Bean 
    public GraphDatabaseService graphDatabaseService(@Value("${neo4j.location}") String neo4jDatabaseLocation) { 
     return new GraphDatabaseFactory() 
       .newEmbeddedDatabase(neo4jDatabaseLocation); 
    } 
    ... 
}